Past studies in our laboratory have indicated that some of the membrane-dependent processes in brain are altered by ethanol. Ethanol may exert its primary action on membrane functions by changing the fluidity and biochemical properties of the neuronal membranes. Prolonged embedding of the membranes with ethanol may promote an adaptive change on the membrane-dependent processes. The present investigation is a continuation to evaluate the alcohol-membrane interaction hypothesis of alcoholism and to examine the adaptive mechanism leading to development of physical dependence. Specifically, we will investigate the dynamic state of membrane lipids in CNS after acute and chronic ethanol treatments. For acute ethanol study, ethanol will be administered to rats using an intragastric intubation technique. For chronic ethanol study, a Lieber De Carli liquid diet will be pair-fed to rats for 21 days. The synaptic plasma membranes (SPM) and myelin will be isolated from the cerebral cortices of control and alcohol-treated animals by differential and sucrose density gradient centrifugation and their lipid composition will be analyzed by thin-layer and gas-liquid chromatographic technique and their protein profile determined by SDS-gel electrophoresis. In addition, the metabolic activity of phosphoglycerides and their acyl groups in brain membranes will be evaluated after acute and chronic ethanol treatment. Experiments will include assaying key enzymes, responsible for metabolism of these membrane components. For better correlation, some of the membrane functions, such as (Na+ + K+)-ATPase, high affinity choline uptake and norepinephrine uptake activities will be examined under similar conditions. It is anticipated that the results of this investigation will lead to further understanding of the alcohol-membrane interaction in brain and the biochemical basis of alcoholism.